function yz() {
  event.preventDefault();
  const user = document.getElementById("username").value;
  const pwd = document.getElementById("password").value;
  if (user == "admin" && pwd == "123") {
    alert("登录成功");
    window.location.href = "http://47.116.207.219/homePage";
  } else {
    alert("用户名或密码错误");
    document.getElementById("username").value = "";
    document.getElementById("password").value = "";
  }
}